There are spark plugs from the related art in various designs. The spark plugs from the automobile field may have a central electrode and a ground electrode. Spark plugs of this type are mass-produced parts, which may typically have a service life of 100,000 km or more. This is achieved, for example, in that noble metals having improved corrosion and erosion properties are used as the electrode wear surface. In the case of stationary internal combustion engines, which are typically operated using combustible gases, such as natural gas, sewage gas, landfill gas, biogas, or hydrogen, the spark plug service life is approximately 2,000 operating hours. In particular in turbocharged stationary internal combustion engines, these run times are only achieved with difficulty using the known spark plugs from the motor vehicle application. Gas engines typically have a higher compression and therefore react significantly more sensitively to an increase in the distance of the electrode, which continuously increases during operation due to electrode wear. Because stationary engines are frequently also used in continuous operation, spark plug change is necessary after only approximately 90 days.
A spark plug from U.S. Pat. No. 5,751,096 B1 has one central electrode and two diametrically opposing ground electrodes. The ground electrodes are situated diametrically opposite one another in a vertical orientation in the longitudinal direction of the spark plug, parallel to the central electrode. As a result of the two ground electrodes, a relatively large ignition range may be ensured on the spark plug, in particular by two electrode gaps.
Furthermore, a spark plug from EP 0 569 787 A1 has a central electrode, a ground electrode, and an intermediate electrode. The intermediate electrode is situated in an area between the central electrode and the ground electrode, the intermediate electrode forming a separate electrode gap with both the central electrode and the ground electrode. Two ignition sparks, namely one ignition spark per electrode gap, may be generated in this way.